The absorption spectrum refers to the range of wavelengths of light that are absorbed by a particular substance. When light passes through a substance, such as a gas, liquid, or solid, it interacts with the atoms or molecules in that substance. The atoms or molecules can absorb specific wavelengths of light, which causes them to transition from a lower energy state to a higher energy state.
The absorption spectrum is typically represented graphically, with the wavelength of light plotted on the x-axis and the amount of light absorbed on the y-axis. The spectrum shows peaks or bands at specific wavelengths where absorption occurs. The intensity of the peaks or bands indicates the amount of light absorbed at each wavelength.
The absorption spectrum is unique to each substance and is determined by the electronic structure and properties of the atoms or molecules within it. It can be used to identify and characterize substances, as different substances have characteristic absorption patterns.
It's worth noting that the absorption spectrum can also be observed in other regions of the electromagnetic spectrum beyond visible light, such as ultraviolet (UV), infrared (IR), and microwave frequencies, depending on the energy transitions involved in the substance being studied.